Donald Trump's strange -- and alarming -- campaign for president is not without precedent, but not since Pat Buchanan in 1990 has there been a political figure who managed to combine and exploit so many hateful aspects of our politics.

That was the year Pat Buchanan said the next war in the Middle East might be proposed by types like A.M. Rosenthal, Henry Kissinger, Richard Perle and Charles Krauthammer, but would be fought by "American kids with names like McAllister, Murphy, Gonzales and Leroy Brown."

It wasn't hard to get the message, which topped off Mr. Buchanan's usual isolationist rhetoric with an unmistakably anti-Semitic appeal. We could have been back in the 1930s listening to Father Coughlin, Gerald L.K. Smith or Charles Lindbergh.

What a contrast Pat Buchanan's words made with the always winning presence of Ronald Reagan, who spoke two years later at the Republican National Convention in Houston. He was there to deliver a farewell address before fading into the mists of his Alzheimer's -- and proceeded to do so with his usual grace. And his usual appeal to keep faith with the American Dream.

The Gipper knew that America, the City upon a Hill, embraces the hopes of not just native-born but immigrant Americans from around the world. A son of immigrants, I remember brushing away a tear at his words, and his understanding of what America has always represented in the world -- a new beginning -- and, Lord willing, will always represent.

Ronald Reagan's eloquence that night was matched, as it so often was, by his good will. Everybody in the Astrodome seemed to rise as one at the conclusion of Reagan's touching words.

What a contrast these two politicians made. Buchanan and Reagan. Dark and light. One always looking to the future with bright hope, the other back toward the uglier shadows of our history.

My immigrant mother knew nothing ugly about America, or if she did, allowed no mention of it in her house, or in her presence. She reserved a special contempt for anyone who might complain about this country. Amerikaner-geboren, she would call me when I made the usual teenage gripes, as if to say: What do you know about real troubles? War, starvation, oppression....

And there was the special way my mother pronounced the very word America -- as if she were saying Hope, or Gratitude, or Promised Land -- and the special way she would say Europe: with absolute contempt. She was still the 19-year-old immigrant girl who couldn't wait to shake the dust of the old country off her feet. In her old age, one of her rich friends suggested she take a European vacation. The sneer in her voice when she replied was as unmistakable as her accent: "My dear, I vas born dere."

This year the role of the Ugly American who has embraced the worst aspects of American politics is being played by the one and only (thank goodness) Donald Trump, who has managed to touch every malicious note in the current debate over immigration:

First he would junk the birthright clause of the 14th Amendment that makes anyone born on these shores a citizen of these United States. (With the possible exception of some American Indians, who can claim to be part of their own separate nations.) "What they're doing," Donald Trump says of those prospective mothers and fathers who may have come here without the right papers but wanted to make sure their child would be born an American, "they're having a baby. And then all of a sudden, nobody knows ... the baby's here." And becomes a full-fledged American citizen. Welcome, fellow American!

Nobody is about to repeal the 14th Amendment at this late date (thank goodness), but Donald Trump knows how to appeal to our meanest instincts, and seems to enjoy doing it. It's not a pretty sight.

Most Americans want to shore up our southern border, too, but The Donald would make Mexico pay for it no matter where those illegal immigrants might have come from -- Guatemala, say, or Honduras -- or, like most illegals, they may have just overstayed their visas instead of sneaking across the Rio Grande.

But what are the mere facts of the matter to The Donald? He's not out to solve problems but create them, to excite his fans and recruit even more of them from the ranks of the ill-tempered and ill-informed. His followers should be called the Sorehead faction of the Republican Party, and his views on immigration could be summed up as the Bad Neighbor Policy, for they come across as a composite of every anti-American stereotype the rest of the word has of us: bumptious, ignorant, aggressive, chauvinistic, xenophobic....

There's more, a lot more. Here's a candidate for president who's opposed letting immigrants use ties to family already here as a basis for admission to this country -- the way my mother was brought over by my grandmother, the grand matriarch and Mother Courage of the whole family. Donald Trump wouldn't even let immigrants here without the proper papers send money home to those they've left behind. So much for family values.

The Donald is addicted to the snap judgment, or rather the snap prejudice. He would deport "criminal aliens" -- without setting up a clear way to distinguish between the "criminal element" and those illegals who have worked hard, paid their taxes, raised their families and generally been good citizens for years without being actual citizens. And it's not just illegal immigration Donald Trump rails against; he would halt the perfectly legal kind, too -- at least for a time.

Other candidates running for the Republican presidential nomination may talk sense about immigration, illegal and otherwise, and even appeal to the enlightened self-interest of this nation of immigrants. Candidates like Jeb Bush and Marco Rubio and, perhaps the most decent of the bunch, Ohio'sJohn Kasich, a governor used to proposing -- and carrying out -- practical policies. Instead of appealing to our worst, meanest instincts.

On second thought, maybe it's not Pat Buchanan's followers but a political party more remote in time that offers the more exact parallel with Donald Trump's hateful politics: the Know-Nothings of the 1850s, when the Union was fast coming apart. Sectional, ethnic and political divisions were mounting to new and fevered highs, providing the perfect environment for demagogues of every persuasion.

The Know-Nothings got their nickname because, when its members were asked about their party, they would claim to "know nothing." And they certainly knew nothing about how to unite the country. Any more than Donald Trump does now. Their specialty, like his, was dividing it. And their scapegoat for all the country's problems: Germans in the Midwest, Irish in the East, Roman Catholics anywhere. But the party didn't last long. Having preached divisiveness, it was soon divided itself between its Northern and Southern wings, and never made it to the most divisive of American presidential elections in 1860, the one that set off the Civil War.

Now we have Donald Trump -- a modern Know-Nothing -- doing his best, or rather worst, to divide the rest of us. But even in the midst of the quadrennial madness known as an American presidential election, there are still thinking Americans who refuse to swallow his bait. May they multiply and prosper, for United We Stand.